Circuit interrupter



CI. 24, 1944. Q H, HQDGKlNs 2,361,202

CIRCUIT INTERRUPTER Filed sept. 1, 1942 C) QQ y@ v v qdfYl/ATTOI Patented Oct. 24, 1944 i UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER Charles H. Hodgkins, Fairfield, Conn., assigner to The Bryant Electric Company, Bridgeport, Conn., a corporation of Connecticut Application September 1, 1942, Serial No. 456,897

(Cl. 20o-67) 14 Claims.

This invention relates to electric circuit interrupters in general, and more especially to snap- ,acting switches.

One object of this invention is to provide a novel form of flexible snap-acting switch blade which is relatively simple in form yet eflicient in operation.

Another object ofthis invention is to provide a novel arrangement of a snap switch of the type described and supporting and actuating means therefor.

These and other objects of this invention will become more apparent; upon consideration of the following detailed description of a preferred embodiment thereof, when taken in connection with the attached drawing, in which:

Figure 1 is an elevational view of a switch embodying this invention with the casing cover i Fig. 4 is a longitudinal central section view` taken on the line IV-IV of the switch blade shown in Fig. 3, and

Fig. 5 is a partial section of the switch shown in Fig. 1 taken substantially on the line V-V thereof.

The switch illustrated in the drawing is mounted in a dust-proof housing which is formed with a generally rectangularly shaped frame 2, which may be of a single strip of metal bent to rectangular shape and .having the ends thereof secured together at 4, as by welding or the like. plete the switch enclosure, and these plates are secured in position at opposite sides of rectangular frame 2 by a pair of through bolts I2. Through bolts I2 are preferably secured, respectively, at opposite ends of Supporting strips 9 and II. These supporting strips are secured at the other ends thereof as by rivets I3 to side plate 8. Strips 9 and II preferably have some resiliency so that on drawing up through bolts l2 predetermined resilient pressure will be exerted thereby on side plates 6 and 8 and insu-v lating sheets Il). Sheets of insulating material I0, such as a-brous insulating material, are

preferably interposed between side plates 6 and 8 and rectangular frame 2, as shown. Side plate 8 is provided at opposite ends thereof, with in- Opposite side plates 6 and 8 comtegral apertured supporting ears I4, for the purpose of mountingthe switch casing.

Within the switch casing, an insulating supporting plate I6, for example, of fiber or the like, is secured to side iplate 8, for example, as by bolts I8 secured to the side plate, with spacing collars 20 interposed between insulating plate I6 and side cover plate 8, to maintain supporting plate I 6 in spaced relation with respect to plate 3. Supporting plate I6 has mounted thereon a contact supporting bracket 22, for example, as by rivets 23,'and this bracket is provided with an angularly extending portion for supporting a contact 24. Contact 24 should be of some arc resistant material such, for example, as silver or silver alloy. A switch blade supporting bracket 42t. is also mounted on plate I6 at a. point spaced from bracket 22, and may also be secured to plate I6 by rivets 23. Each bracket is provided with a terminal screw 21 for securing a conductor thereto. Blade supporting bracket 28 is provided with an outstanding base 23, provided at the edge adjacent the end of the casing, with integral spaced circular bosses 30, and at the opposite ends thereof with integral spaced rectangular projections 32.

A switch blade 34 is ,provided at one end thereof with spaced apertures 36 spaced apart the same distance as supporting bosses 30 to receive screws 38 threaded into bosses 30, for securing the blade to bracket base 28. Switch blade 34 is provided with a generally rectangular portion 40 and a tapering end portion 42 having an aperture 43 in the outer end thereof for securing thereto a contact element 45, as by riveting or the like. A circular aperture 44 is provided through the body of blade 34at a point closer to the rectangular end thereof than to aperture 43. In forming blade 34, it may be stamped out of a sheet or strip of any good flexible and resilient conducting material such for example as a copper alloy, and thereafter it is subjected to a pressing operation in the area indicated at 46. For this operation, the blade is prefer- 48, which is sensitive to pressure 'exerted thereon for causing a reversal in the curvature or concavity of the blade as the result of very small movement on the sensitive area. Pressure applied to sensitive area 48 of these switch blades, provides, however, relatively large movement of the opposite end of the blade, and furthermore this movement takes place with a snap action due to the sudden reversal in curvature of the blade. The action is enhanced by the particular means of supporting the switch blade illustrated, wherein the blade is supported at four spaced points arranged substantially at the corners of a rectangle so that the blade is given support at spaced points arranged about sensitive area 48. It will be noted that blade aperture 44 is positioned adjacent rectangular supporting projections 32, and substantially at the point of maximum longitudinal and lateral curvature of the blade, to render the blade more flexible at this point, where maximum flexure occurs.

As shown in Fig. 1, the blade is supported so that its contact 45 engages xed contact 24 to close the circuit between brackets 22 and 26. Accordingly, to open the circuit, an actuating lever 50 is provided with spaced parallel flanges 52 intermediate the ends thereof apertured for the reception of a pivot stud 54 secured to side plate 8. A biasing spring 56 is coiled about pivot stud 54 intermediate flanges 52, and presses against lever D at one end, and against a stop stud 51 at the other end to bias lever 50 in a counterclockwise direction as viewed in Fig. 1. Biasing spring 55 should be strong enough so that actuating projection 58 on the lever will engage sensitive area 48 of the blade with sufficient pressure to cause reversal of curvature of the blade and consequent opening of the switch. Actuating projection 58 on lever 50 should be of insulating material in order to insulate lever 50 from the circuit, preferably a molded insulating material mounted in a suitably provided aperture in the end of lever 50.

For controlling movement of lever 50, there is mounted at the opposite end of the switch casing a supporting sleeve 60 having a reduced outer end 62 spun over the edges of an aperture provided in switch frame 2. The other end of supporting sleeve 60 has an aperture therethrough reduced in size to form an internal shoulder 64. A push rod 66 slidably ts in the aperture at the inner end of sleeve 60 and is provided with a stop shoulder 68 at its inner end to engage the inner end of supporting sleeve B0 to limit outward movement of the push rod. The push rod has at its extreme inner end an operating ange 'I0 positioned to engage the adjacent end of operating lever 50. The outer end of push rod 66 is provided with a push button 'l2 having a socket for receiving the push rod, and is secured thereto as by a pin 14. A coiled compression spring 16 is mounted within supporting sleeve 60, and reacts between push button 'l2 and shoulder 64 of the sleeve to normally urge the push rod outwardly relative to the switch casing.

Push button spring I6 should be strong enough to overcome the force exerted by spring 56 so that it is operable to maintain actuating projection 58 on lever 50 in the position shown in Fig. i, wherein it is out of engagement with the sensitive area of the blade. Consequently in order to open the switch push button l2 is depressed thereby permitting spring 56 to rotate lever 50 in a counterclockwise direction to cause engagement of actuating projection 5B with sensitive area 48 of the switch blade. This will cause reversal of curvature of the blade as explained above, and operate to open the circuit with a snap action. One end of rectangular frame 2 may be suitably apertured for receiving a conduit fitting 18, through which conductors may be led into the switch casing.

The switch blade described above is of such simple form that it may be easily cut out and formed in one or two stamping operations. 'I'he blade itself, shown in Figs. 3 and 4 is designed with certain of the metal thereof removed (aperture 44) at the point where maximum ilexure of the blade occurs. The particular means of supporting the blade at four spaced points of limited area, coupled with the particular formation of the blade to bring sensitive area 48 within the space enclosed by the supporting points 30, 32, provides an especially easy operation of the blade which lends itself particularly well to the specific operating mechanism disclosed, as well as providing an eillcient snap-action in opening and closing the circuit.

It will be noted that the force exerted on the push button 12 does not cause deflection of blade 34, but that the latter is acted upon only by a force which may be easily predetermined by the construction of spring 56. Moreover, the amount push button 12 is depressed is immaterial beyond a predetermined minimum travel, because the push button has overtravel with respect to lever 50.

A stop bracket 5| is preferably also mounted on supporting plate I6 below contact supporting bracket 22 and spaced therefrom. The purpose of this bracket is to engage the free end of blade 34 in its switch opening movement to prevent complete reversal of curvature of the blade, so that when push button 12 is released and moved upwardly by spring 16, to rotate lever 50 in a clockwise direction and remove the pressure of' spring 56 on sensitive area 48 of the blade, the blade will then automatically return into engagement with contact 24.

From the foregoing it is apparent that the switch of this invention embodies a novel form of snap acting blade element. together with novel supporting means therefor. This invention also comprehends actuating means for such a blade, such that the blade is subjected solely to a predetermined operating pressure, independent of the pressure exerted on the actuating means, or the travel imparted thereto.

Having described a preferred embodiment of the invention in accordance with the patent statutes, it is desired that the invention be not limited to this particular embodiment because it will be obvious particularly to persons skilled in the art that many modiiications and changes may be made therein without departing from the broad spirit and scope of this invention. Therefore, it is desired that this invention be interpreted as broadly as possible and be limited only as required by the prior art.

I claim as my invention:

l. In a switch. supporting means, an elongated, solid blade of flexible and resilient conducting material mounted at one end on said supporting means with the other end of said blade being free to move, a contact carried by said other end of said blade, a cooperating contact carried on said supporting means, a single opening through said l Y l bladelocated entirely adjacent the mounting of said one end lthereoand the material ofws'aid -blade atleast'at one side of said'aperture being deformed to cause the blade to assume'a flexed material mounted at one end on said supporting,

means with the other end of said blade being free to move, a contact carried by said other end of said blade, a cooperating contact carried on said supporting means, a single substantially circular aperture through said blade located entirely adjacent the mounting of said one end thereof, the material of said blade at least at one side of said aperture being deformed to cause the blade to assume a flexed condition and providing an area adjacent said one end of the blade sensitive to pressure to cause movement of the other end of the blade with a snap action, and means for exerting pressure on said sensitive area to at least cause disengagement of said contacts with a snap action.

3. In a switch, supporting means, an elongated, solid blade of flexible and resilient conducting material mounted at one end on said supporting means with the other end of said blade being free to move, a contact carried by said other end of said blade, a cooperating contact carried on said supporting means, an aperture through said blade adjacent said one end thereof and the material of said blade for a limited area entirely surrounding said aperture being deformed to cause the blade to assume a flexed condition, and providing an area adjacent said one end of the blade sensitive to pressure to cause movement of the other end of the blade with a snap action, and means for exerting pressure on said sensitive area to at least cause disengagement of said contacts with a snap action.

4. In a switch, supporting means, an elongated, solid blade of flexible and resilient conducting material mounted at one end on said supporting means with the other end of said blade being free to move, a contact carried by said other end of said blade, a cooperating contact carried on said supporting means, an aperture through said blade adjacent but spaced from said one end thereof, and the material of said blade about a substantial portion of said aperture being deformed over an area elongated in the direction of the longitudinal axis of said blade to cause the blade tc assume a flexed condition, and providing an area adjacent said one end of the blade sensitive to pressure to cause movement of the other end of the blade with a snap action, and means for exerting pressure on said sensitive area to at least cause disengagement of said contacts with a snap action.

5. In a switch, supporting means, an elongated, solid blade of flexible and resilient conducting material mounted at one end on said supporting means with the other end of said blade being free to move, a contact carried by said other end i.' said blade, a cooperating contact carried on said supporting means, an aperture through said blade adjacent but spaced from said one end thereof, and the material of said blade about a substantial portion of said aperture being deformed over an area elongated in the direction of the longitudinal axis of said blade with said aperture locatedl adjacent the end of said area more remote from said one end of said blade to cause the blade to assumea flexed condition, and providing an area adjacent said one end of the blade sensitive to pressure to cause movement of the other end of the blade with a snap action, and means for exerting pressure on said sensitive area to at least causedisengagement of said contacts with a snap action. Y

6. In a switch, an elongated solid blade of flexible and resilient conducting material, spaced means supporting each side of said blade at one end thereof and at an intermediate point leaving the other end of said blade free, contact means carried by,y the free end of said blade, cooperating contact means fixed relative to said support, an aperturev through said blade at a point adjacent said intermediate supporting means, and the material of said blade at least at one side of said aperture being deformed to cause the blade to assume a flexed condition and providing an area intermediate said supporting means sensitive to pressure to cause movement of the other end of the blade with a snap action, and means for exerting pressure on said sensitive area to at least cause disengagement of said contacts with a snap action.

7. In a switch, an elongated solid blade of' flexible and resilient conducting material, spaced means supporting each side of said blade at one end thereof and at anintermediate point leaving the other end of said blade free, contact means carried by the free end of said blade, cooperating contact means fixed relative to said support, an aperture `through said Ablade at a point adjacent said intermediate supporting means and the material of said blade being deformed over an area extending from said aperture into the space between said supporting means, to cause the blade to assume a flexed condition and providing an area intermediate said supporting means sensitive to pressure to cause movement of the other end of the blade -with a snap action, and means for exerting pressure on said sensitive area to at least cause disengagement of said contacts with a snap action.

8. A switch blade element comprising an elongated solid strip of flexible and resilient conducting material, a single aperture located entirely adjacent but spaced from one end of said element, and the material of said blade at least at one side of said aperture being deformed.

9. A switch blade element comprising an elongated solid strip of flexible and resilient conducting material, an aperture adjacent but spaced from one end of said element and the material of said element being deformed over a limited elongated area including at least one side of said aperture and extending toward said one end of said element.

10. A switch blade element comprising an elongated solid strip of flexible and resilient conducting materlal, an aperture adjacent but spaced from one end of said element, and the material of said blade at least at one side of said aperture being deformed by depressing a limited area of one side of said element, the other side being undepressed.

ll. In a switch, an elongated solid blade of flexible and resilient conducting material, a base having integral projecting spaced means supporting opposite sides if said blade at one end thereof and at an intermediate point leaving the other end of said blade free, contact means carried by the free end of said blade, cooperating contact means fixed relative to said support, an aperture through said blade at a point adjacent said intermediate supporting means, the material of said blade at least at one side of said aperture being deformed to cause the blade to assume a iiexed condition and providing an area intermediate said supporting means sensitive to pressure to cause movement of the other end of the blade with a snap action, and means for exerting pressure on said sensitive area to at least cause disengagement of said contacts with a snap action.

12. In a switch, supporting means, an elongated, sold blade of flexible and resilient conducting material mounted at one end on said supporting means with the other end of said blade being free to move, a contact carried by said other end of said blade, a cooperating contact carried on said supporting means, an aperture through said blade adjacent said one end thereof, and the material of said blade at least at one side of said aperture being deformed to cause the blade to assume a exed condition and providing an area adjacent said one end of the blade sensitive to pressure to cause movement of the other end of the blade with a. snap action, resilient biased means for exerting pressure on said sensitive area to at least cause disengagement of said contacts with a snap action, and resiliently biased control means normally maintaining said pressure exerting means inactive but adapted when actuated to permit said pressure exerting means to actuate said switch.

13. In a switch, separable contacts, means for opening and closing said contacts with a snap action comprising a iiexible member having a portion sensitive to pressure to cause flexing of said member with a snap action, an actuator for said member biased to exertl operating pressure on said sensitive portion by direct engagement with said sensitive portion, movable operating means biased in one direction for normally preventing said actuator from exerting operating pressure on said member, and said operating means being movable in an opposite direction to permit said actuator to operate said member independently of said operating means, whereby said member is subject only to the biasing force of said actuator.

14. In a switch, separable contacts, means for opening and closing said contacts with a snap action comprising a flexible member having a portion sensitive to pressure to cause iiexing of said member with a snap action, an actuator for said member biased to exert operating pressure on said sensitive portion by direct engagement with said sensitive portion, movable operating means biased in one direction for normally maintaining said actuator spaced from said member, and said operating means being movable in an opposite direction to permit said actuator to engage and operate said member independently of said operating means, whereby said member is subject only to the biasing force of said actuator.

CHARLES H. HODGKINS. 

